I need some jetting help with my new 686 jetting. I am running a full CT pipe setup w/K&N pro flow. The airbox lid is off. I have a stage II cam and 11:1 piston. Like the title, I am running at sea level and 100 octane. Please give your opinions...

 

Buy 39mm FCRs or have your stock carbs modified by a reputable Raptor builder.

 

Believe me, if I had the money, I would definitely go with the FCR's. I've heard of people modifying their stock carbs. What all is done to the stockers when they are modified? Will 195/200 and bigger pilot jets not work with my setup with out your recommendation?

 

try a dyno jet kit, use their needles and springs set up how they suggest, but run 27.5 piolt jets, turn your a/f screw out 3 turns, and start with 185 and 190 main jets from dyno jet, that is probally the best starting point to go with. After that run it for awhile so you can get a good reading on your plug and adjust up or down from there. Or start from there and leave all your plastic off and just go up and down on your jets and make some hard runs to find out which jets pull best.

 

With my mods Im at 185/190....so Im guessing you would be ok with 180/185...no airbox and that nology wire I have make a difference.

 

People are useing the duel petcock and modifying the needle valves. Probably a couple other little secrets that they won't share. For the duel petcocks you have to drill into and tap in a fitting to the other carb to connect a gas line to it. As for the needle valves you can buy needle valve sets for a BSR42 Mikuni carb from the grizzly to accomplish the need for more fuel into the carbs. Here are some pics of the differences.

Pic 1 stocker on the right
Pic 2 stocker on the left

 

I already have a dual feed setup on my carbs and I was going to install the 185/190 mains and 27.5 pilots. My jet kit is from CT and my needle clips are 3 from the top. I was going to start off with this unless otherwise conviced.

 

If you don't increase the needle valve size jetting up is useless. Your starting point sounds good.